Fabrication And Properties Of Water-based Copper Composite Paste For Low Melting Point Metal Reinforcementing

With the popularization of concepts such as intelligence,automation and portability,people's functional requirements for electronic products are also increasing.In order to meet the special requirements of device manufacturing,developing green and reliable slurry system is one of the most basic and effective strategies,which can significantly avoid the increase of equipment cost and the complexity of preparation process.Based on the development of a new water-based slurry system,this paper explores the influence of the composition of water-based carrier,low melting point metal bonding phase and sintering process parameters on the properties of conductive slurry.1.The selection and optimum proportion of water-based carrier components and their effects on the conductivity,micro-morphology,printability and stability of slurry were studied.The results showed that the optimum composition and proportion of the new water-based carrier were as follows: thickener(xanthan gum): dispersant(PEG-400):rheological agent(Tween-80): deionized water: defoamer(GP-330)=0.5:1.5:0.5:0.1:97.4,and its influence on slurry performance was as follows:the proportion of water-based carrier.2.In this paper,the effects of the type and content of low melting point metal and the proportion of water-based carrier on the conductivity of conductive adhesive were studied.The results show that among the three factors,the type of low melting point metal has the greatest influence on the slurry performance,followed by the content of low melting point metal,and the proportion of water-based carrier has the least influence.Based on the results analysis and model fitting of the above test data,the box Behnken test results were optimized by design expert software,and the optimal slurry formula was obtained as follows: The type of low melting point metal was selected as Bi,whose content in the water-based paste is 10.6%,while the water-based carrier accounts for 27.12% and copper powder accounts for 62.28%.The resistivity of low melting point metal water-based composite paste is 1.73m?·cm.Compared with pure copper paste,the conductivity of copper paste is increased by94.67%.3.The mechanism of low melting point metal Bi used as binder to enhance the properties of slurry was studied.Results show that the metal Bi lower sintering temperature and at the same time in the process of preparation for the charge transfer between the metal and polarity-nonpolar conversion principle can better fill the pores between copper particles,help the various components of film together,form a benign conductive path,improve the electrical properties and adhesion strength of water-based paste.4.The influence of sintering process on properties of low melting point metal water-based copper composite slurry was studied.The results show that the optimum sintering process parameters in the preparation process are as follows: the water-based composite paste drying time is 25 min,and the sintering temperature is600?.At this time,the conductivity is the best,and the resistivity is as low as 1.48m? · cm.Compared with pure copper paste,the conductivity of copper paste is increased by 95.43%.The film is densified and the conductive network is complete,showing excellent conductivity and microscopic morphology.